:root {
  --bg: #1b1a18;
  --card: #262522;
  --border: #3a3833;
  --text: #eeece6;
  --sub: #a29f96;
  --accent: #d97757;
  --accent-text: #1b1a18;
  --ok: #6fcf97;
  --code: #2f2d29;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}
@media (prefers-color-scheme: light) {
  :root {
    --bg: #f6f5f2; --card: #ffffff; --border: #e3e0d8; --text: #1f1e1b; --sub: #5f5c55;
    --accent: #b8532f; --accent-text: #ffffff; --ok: #2e7d4f; --code: #f0ede6;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font: 17px/1.6 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
a { color: var(--accent); }
a:focus-visible, button:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; border-radius: 6px; }
.wrap { max-width: 960px; margin: 0 auto; padding: 0 20px; }

header.top { display: flex; align-items: center; gap: 12px; padding: 18px 0; }
header.top .brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 18px; color: var(--text); text-decoration: none; }
header.top .brand img { width: 32px; height: 32px; border-radius: 8px; }
header.top nav { margin-left: auto; display: flex; gap: 18px; font-size: 15px; }
header.top nav a { color: var(--sub); text-decoration: none; }
header.top nav a:hover { color: var(--text); }

.hero { padding: 56px 0 40px; }
.hero h1 { font-size: clamp(32px, 6vw, 52px); line-height: 1.12; margin: 0 0 18px; letter-spacing: -0.02em; text-wrap: balance; }
.hero p.lead { font-size: clamp(18px, 2.4vw, 21px); color: var(--sub); max-width: 640px; margin: 0 0 28px; }
.stores { display: flex; flex-wrap: wrap; gap: 12px; }
.store {
  display: inline-flex; flex-direction: column; justify-content: center; min-height: 56px; padding: 8px 22px;
  border-radius: 12px; text-decoration: none; font-weight: 700; font-size: 17px;
  background: var(--accent); color: var(--accent-text); border: 1px solid var(--accent);
}
.store.alt { background: transparent; color: var(--text); border-color: var(--border); }
.store small { font-weight: 500; font-size: 12px; opacity: 0.85; }
.store:hover { filter: brightness(1.08); }
.notice { display: none; margin-top: 16px; padding: 12px 14px; border: 1px solid var(--border); border-radius: 10px; color: var(--sub); max-width: 640px; }
.notice.show { display: block; }

section { padding: 40px 0; border-top: 1px solid var(--border); }
section h2 { font-size: 28px; margin: 0 0 8px; letter-spacing: -0.01em; }
section p.intro { color: var(--sub); margin: 0 0 24px; max-width: 640px; }

.steps { list-style: none; margin: 0; padding: 0; display: grid; gap: 14px; counter-reset: step; }
.steps li { counter-increment: step; background: var(--card); border: 1px solid var(--border); border-radius: 14px; padding: 18px 18px 18px 62px; position: relative; }
.steps li::before {
  content: counter(step); position: absolute; left: 18px; top: 18px; width: 30px; height: 30px; border-radius: 50%;
  background: var(--accent); color: var(--accent-text); font-weight: 700; display: grid; place-items: center; font-size: 15px;
}
.steps h3 { margin: 2px 0 6px; font-size: 18px; }
.steps p { margin: 0; color: var(--sub); }

pre {
  background: var(--code); border: 1px solid var(--border); border-radius: 10px; padding: 12px 14px; margin: 12px 0 0;
  font: 14px/1.5 var(--mono); color: var(--text); overflow-x: auto; white-space: pre;
}
code { font-family: var(--mono); font-size: 0.92em; background: var(--code); padding: 1px 5px; border-radius: 5px; }
pre code { background: none; padding: 0; font-size: inherit; }

.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 14px; }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 14px; padding: 18px; }
.card h3 { margin: 0 0 6px; font-size: 17px; }
.card p { margin: 0; color: var(--sub); font-size: 15.5px; }

ul.plain { margin: 0; padding-left: 20px; color: var(--sub); }
ul.plain li { margin-bottom: 8px; }
ul.plain strong { color: var(--text); }

footer { border-top: 1px solid var(--border); padding: 28px 0 44px; color: var(--sub); font-size: 14px; }
footer .links { display: flex; flex-wrap: wrap; gap: 18px; margin-bottom: 12px; }
footer a { color: var(--sub); }

.doc { padding: 32px 0 48px; max-width: 720px; }
.doc h1 { font-size: 34px; margin: 0 0 6px; }
.doc h2 { font-size: 21px; margin: 30px 0 8px; }
.doc p, .doc li { color: var(--sub); }
.doc strong { color: var(--text); }
.doc .date { color: var(--sub); font-size: 14px; }

@media (max-width: 520px) {
  header.top nav { gap: 12px; font-size: 14px; }
  .hero { padding: 36px 0 28px; }
  .store { flex: 1 1 100%; align-items: center; text-align: center; }
}
header.top nav a { white-space: nowrap; }
@media (max-width: 520px) {
  /* Trên điện thoại chỉ giữ nút đổi ngôn ngữ; hai mục còn lại nằm ngay bên dưới khi cuộn. */
  header.top nav a:not([lang]) { display: none; }
}

/* Nhật ký thay đổi */
.changelog h2 { font-size: 26px; margin: 36px 0 4px; padding-top: 24px; border-top: 1px solid var(--border); }
.changelog h2:first-of-type { border-top: none; padding-top: 0; }
.changelog h2 .date { font-size: 14px; font-weight: 400; margin-left: 10px; }
.changelog h3 { font-size: 17px; margin: 22px 0 8px; color: var(--text); }
.changelog ul { padding-left: 20px; margin: 0; }
.changelog li { margin-bottom: 7px; }
.changelog .source { margin-top: 40px; font-size: 14px; }